The present invention relates in general to radiant energy imaging and more particularly concerns novel apparatus and techniques for rapidly providing an image of the whole body of a patient who has been injected with a suitable radioactive tracer chemical. The invention is characterized by a number of features that enable a diagnostician to rapidly obtain considerable information about the patient in a relatively short time with safety, with minimal discomfort to the patient and in a form that facilitates greater and repeated examination and processing by a computer or other automatic data processing device.
A useful diagnostic tool for essentially noninvasively diagnosing the condition of a patient is a radiant energy image of the whole body produced by injecting a suitable radioactive tracer chemical into the patient and then scanning the patient to effectively provide a map of the radiation intensity from the patient.
A major problem in obtaining these maps is the length of time for obtaining the radiant energy image of suitable resolution. Prior art approaches typically require longer than twenty minutes to produce radiant energy images of the whole body of a patient. To keep an ill patient still for such a long period is difficult and discomforting to the patient.
One prior art approach is disclosed in U.S. Pat. No. 3,509,341 using a multichannel scanner having a linear array of scintillation crystals comprising radiation detectors. The linear detector array is parallel to the long axis of the patient and reciprocates in a direction normal to the length of the array. After each stroke of the transverse reciprocal motion, typically an amplitude of 45 cm, the whole array indexes a fraction of an inch in the longitudinal direction. This scan-and-step sequence repeats until the sum of the lengthwise increments just equals the separation between the focal points of the array to complete a scan for an area of width corresponding to the transverse scan amplitude, typically 45 cm, and the length of the array; that is, the number of detectors multiplied by the separation between detectors. This approach necessarily limits the size of a single frame or scan-area to an area much smaller than the projected area of an adult patient. Thus, to scan the whole body of an adult, several individual frames are required over a time interval longer than that desired. In the commercially available Dynapix system the patient is moved between successive frames.
Accordingly, it is an important object of this invention to provide an improved radiant energy imaging system that overcomes one or more of the disadvantages enumerated above.
It is another object of the invention to achieve the preceding object with a radiant energy imaging system that may scan the whole body in a relatively short interval.
It is a further object of the invention to achieve one or more of the preceding objects with a system that does not subject a patient to appreciable discomfort or anxiety.
It is a further object of the invention to achieve one or more of the preceding objects with a system that provides great flexibility in terms of information density, the ability to monitor the resultant image and to study the image at any time with or without computer or other automatic data processing apparatus assistance.
It is a further object of the invention to achieve one or more of the preceding objects with equipment that is relatively safe and reliable.